src/bin/lttng/commands/create.cpp

   1 /*
   2  * Copyright (C) 2011 EfficiOS Inc.
   3  * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   4  *
   5  * SPDX-License-Identifier: GPL-2.0-only
   6  *
   7  */
   8
   9 #define _LGPL_SOURCE
  10 #include "../command.hpp"
  11 #include "../utils.hpp"
  12
  13 #include <common/compat/time.hpp>
  14 #include <common/defaults.hpp>
  15 #include <common/mi-lttng.hpp>
  16 #include <common/path.hpp>
  17 #include <common/sessiond-comm/sessiond-comm.hpp>
  18 #include <common/uri.hpp>
  19 #include <common/utils.hpp>
  20
  21 #include <lttng/lttng.h>
  22
  23 #include <ctype.h>
  24 #include <popt.h>
  25 #include <signal.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <sys/stat.h>
  30 #include <sys/types.h>
  31 #include <sys/wait.h>
  32 #include <unistd.h>
  33
  34 static char *opt_output_path;
  35 static char *opt_url;
  36 static char *opt_ctrl_url;
  37 static char *opt_data_url;
  38 static char *opt_shm_path;
  39 static int opt_no_consumer;
  40 static int opt_no_output;
  41 static int opt_snapshot;
  42 static uint32_t opt_live_timer;
  43
  44 #ifdef LTTNG_EMBED_HELP
  45 static const char help_msg[] =
  46 #include <lttng-create.1.h>
  47         ;
  48 #endif
  49
  50 enum {
  51         OPT_HELP = 1,
  52         OPT_LIST_OPTIONS,
  53         OPT_LIVE_TIMER,
  54 };
  55
  56 enum output_type {
  57         OUTPUT_NONE,
  58         OUTPUT_LOCAL,
  59         OUTPUT_NETWORK,
  60         OUTPUT_UNSPECIFIED,
  61 };
  62
  63 static struct mi_writer *writer;
  64 static struct poptOption long_options[] = {
  65         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  66         { "help", 'h', POPT_ARG_NONE, nullptr, OPT_HELP, nullptr, nullptr },
  67         { "output", 'o', POPT_ARG_STRING, &opt_output_path, 0, nullptr, nullptr },
  68         { "list-options", 0, POPT_ARG_NONE, nullptr, OPT_LIST_OPTIONS, nullptr, nullptr },
  69         { "set-url", 'U', POPT_ARG_STRING, &opt_url, 0, nullptr, nullptr },
  70         { "ctrl-url", 'C', POPT_ARG_STRING, &opt_ctrl_url, 0, nullptr, nullptr },
  71         { "data-url", 'D', POPT_ARG_STRING, &opt_data_url, 0, nullptr, nullptr },
  72         { "no-output", 0, POPT_ARG_VAL, &opt_no_output, 1, nullptr, nullptr },
  73         { "no-consumer", 0, POPT_ARG_VAL, &opt_no_consumer, 1, nullptr, nullptr },
  74         { "snapshot", 0, POPT_ARG_VAL, &opt_snapshot, 1, nullptr, nullptr },
  75         { "live",
  76           0,
  77           POPT_ARG_INT | POPT_ARGFLAG_OPTIONAL,
  78           nullptr,
  79           OPT_LIVE_TIMER,
  80           nullptr,
  81           nullptr },
  82         { "shm-path", 0, POPT_ARG_STRING, &opt_shm_path, 0, nullptr, nullptr },
  83         { nullptr, 0, 0, nullptr, 0, nullptr, nullptr }
  84 };
  85
  86 /*
  87  * Retrieve the created session and mi output it based on provided argument
  88  * This is currently a summary of what was pretty printed and is subject to
  89  * enhancements.
  90  */
  91 static int mi_created_session(const char *session_name)
  92 {
  93         int ret, i, count, found;
  94         struct lttng_session *sessions;
  95
  96         /* session_name should not be null */
  97         LTTNG_ASSERT(session_name);
  98         LTTNG_ASSERT(writer);
  99
 100         count = lttng_list_sessions(&sessions);
 101         if (count < 0) {
 102                 ret = count;
 103                 ERR("%s", lttng_strerror(ret));
 104                 goto error;
 105         }
 106
 107         if (count == 0) {
 108                 ERR("Error session creation failed: session %s not found", session_name);
 109                 ret = -LTTNG_ERR_SESS_NOT_FOUND;
 110                 goto end;
 111         }
 112
 113         found = 0;
 114         for (i = 0; i < count; i++) {
 115                 if (strncmp(sessions[i].name, session_name, NAME_MAX) == 0) {
 116                         found = 1;
 117                         ret = mi_lttng_session(writer, &sessions[i], 0);
 118                         if (ret) {
 119                                 goto error;
 120                         }
 121                         break;
 122                 }
 123         }
 124
 125         if (!found) {
 126                 ret = -LTTNG_ERR_SESS_NOT_FOUND;
 127         } else {
 128                 ret = CMD_SUCCESS;
 129         }
 130
 131 error:
 132         free(sessions);
 133 end:
 134         return ret;
 135 }
 136
 137 static struct lttng_session_descriptor *create_session_descriptor(const char *session_name)
 138 {
 139         ssize_t uri_count;
 140         enum output_type output_type;
 141         struct lttng_uri *uris = nullptr;
 142         struct lttng_session_descriptor *descriptor = nullptr;
 143         const char *uri_str1 = nullptr, *uri_str2 = nullptr;
 144         char local_output_path[LTTNG_PATH_MAX] = {};
 145
 146         if (opt_no_output) {
 147                 output_type = OUTPUT_NONE;
 148         } else if (opt_output_path) {
 149                 char *expanded_output_path;
 150                 int ret;
 151
 152                 output_type = OUTPUT_LOCAL;
 153                 expanded_output_path = utils_expand_path(opt_output_path);
 154                 if (!expanded_output_path) {
 155                         ERR("Failed to expand output path.");
 156                         goto end;
 157                 }
 158                 ret = lttng_strncpy(
 159                         local_output_path, expanded_output_path, sizeof(local_output_path));
 160                 free(expanded_output_path);
 161                 if (ret) {
 162                         ERR("Output path exceeds the maximal supported length (%zu bytes)",
 163                             sizeof(local_output_path));
 164                         goto end;
 165                 }
 166         } else if (opt_url || opt_ctrl_url) {
 167                 int ret;
 168
 169                 uri_str1 = opt_ctrl_url ? opt_ctrl_url : opt_url;
 170                 uri_str2 = opt_data_url;
 171
 172                 uri_count = uri_parse_str_urls(uri_str1, uri_str2, &uris);
 173                 if (uri_count != 1 && uri_count != 2) {
 174                         ERR("Unrecognized URL format.");
 175                         goto end;
 176                 }
 177
 178                 switch (uri_count) {
 179                 case 1:
 180                         output_type = OUTPUT_LOCAL;
 181                         if (uris[0].dtype != LTTNG_DST_PATH) {
 182                                 ERR("Unrecognized URL format.");
 183                                 goto end;
 184                         }
 185                         ret = lttng_strncpy(
 186                                 local_output_path, uris[0].dst.path, sizeof(local_output_path));
 187                         if (ret) {
 188                                 ERR("Output path exceeds the maximal supported length (%zu bytes)",
 189                                     sizeof(local_output_path));
 190                         }
 191                         break;
 192                 case 2:
 193                         output_type = OUTPUT_NETWORK;
 194                         break;
 195                 default:
 196                         /* Already checked. */
 197                         abort();
 198                 }
 199         } else {
 200                 output_type = OUTPUT_UNSPECIFIED;
 201         }
 202
 203         if (opt_snapshot) {
 204                 /* Snapshot session. */
 205                 switch (output_type) {
 206                 case OUTPUT_UNSPECIFIED:
 207                 case OUTPUT_LOCAL:
 208                         descriptor = lttng_session_descriptor_snapshot_local_create(
 209                                 session_name,
 210                                 output_type == OUTPUT_LOCAL ? local_output_path : nullptr);
 211                         break;
 212                 case OUTPUT_NONE:
 213                         descriptor = lttng_session_descriptor_snapshot_create(session_name);
 214                         break;
 215                 case OUTPUT_NETWORK:
 216                         descriptor = lttng_session_descriptor_snapshot_network_create(
 217                                 session_name, uri_str1, uri_str2);
 218                         break;
 219                 default:
 220                         abort();
 221                 }
 222         } else if (opt_live_timer) {
 223                 /* Live session. */
 224                 if (output_type != OUTPUT_UNSPECIFIED && output_type != OUTPUT_NETWORK) {
 225                         ERR("Unsupported output type specified for live session.");
 226                         goto end;
 227                 }
 228                 descriptor = lttng_session_descriptor_live_network_create(
 229                         session_name, uri_str1, uri_str2, opt_live_timer);
 230         } else {
 231                 /* Regular session. */
 232                 switch (output_type) {
 233                 case OUTPUT_UNSPECIFIED:
 234                 case OUTPUT_LOCAL:
 235                         descriptor = lttng_session_descriptor_local_create(
 236                                 session_name,
 237                                 output_type == OUTPUT_LOCAL ? local_output_path : nullptr);
 238                         break;
 239                 case OUTPUT_NONE:
 240                         descriptor = lttng_session_descriptor_create(session_name);
 241                         break;
 242                 case OUTPUT_NETWORK:
 243                         descriptor = lttng_session_descriptor_network_create(
 244                                 session_name, uri_str1, uri_str2);
 245                         break;
 246                 default:
 247                         abort();
 248                 }
 249         }
 250         if (!descriptor) {
 251                 ERR("Failed to initialize session creation command.");
 252         } else {
 253                 /*
 254                  * Auto-launch the relay daemon when a live session
 255                  * is created using default URLs.
 256                  */
 257                 if (!opt_url && !opt_ctrl_url && !opt_data_url && opt_live_timer &&
 258                     !check_relayd()) {
 259                         int ret;
 260                         const char *pathname = opt_relayd_path ?: INSTALL_BIN_PATH "/lttng-relayd";
 261
 262                         ret = spawn_relayd(pathname, 0);
 263                         if (ret < 0) {
 264                                 lttng_session_descriptor_destroy(descriptor);
 265                                 descriptor = nullptr;
 266                         }
 267                 }
 268         }
 269 end:
 270         free(uris);
 271         return descriptor;
 272 }
 273
 274 /*
 275  *  Create a tracing session.
 276  *  If no name is specified, a default name is generated.
 277  *
 278  *  Returns one of the CMD_* result constants.
 279  */
 280 static int create_session(const char *session_name)
 281 {
 282         int ret, i;
 283         char shm_path[LTTNG_PATH_MAX] = {};
 284         struct lttng_session_descriptor *session_descriptor = nullptr;
 285         enum lttng_session_descriptor_status descriptor_status;
 286         enum lttng_error_code ret_code;
 287         struct lttng_session *sessions = nullptr;
 288         const struct lttng_session *created_session = nullptr;
 289         const char *created_session_name;
 290
 291         /* Validate options. */
 292         if (session_name) {
 293                 if (strlen(session_name) > NAME_MAX) {
 294                         ERR("Session name too long. Length must be lower or equal to %d", NAME_MAX);
 295                         ret = CMD_ERROR;
 296                         goto error;
 297                 }
 298                 /*
 299                  * Check if the session name begins with "auto-" or is exactly "auto".
 300                  * Both are reserved for the default session name. See bug #449 to
 301                  * understand why we need to check both here.
 302                  */
 303                 if ((strncmp(session_name,
 304                              DEFAULT_SESSION_NAME "-",
 305                              strlen(DEFAULT_SESSION_NAME) + 1) == 0) ||
 306                     (strncmp(session_name, DEFAULT_SESSION_NAME, strlen(DEFAULT_SESSION_NAME)) ==
 307                              0 &&
 308                      strlen(session_name) == strlen(DEFAULT_SESSION_NAME))) {
 309                         ERR("%s is a reserved keyword for default session(s)",
 310                             DEFAULT_SESSION_NAME);
 311                         ret = CMD_ERROR;
 312                         goto error;
 313                 }
 314         }
 315
 316         if (opt_snapshot && opt_live_timer) {
 317                 ERR("Snapshot and live modes are mutually exclusive.");
 318                 ret = CMD_ERROR;
 319                 goto error;
 320         }
 321
 322         if ((!opt_ctrl_url && opt_data_url) || (opt_ctrl_url && !opt_data_url)) {
 323                 ERR("Both control and data URLs must be specified.");
 324                 ret = CMD_ERROR;
 325                 goto error;
 326         }
 327
 328         session_descriptor = create_session_descriptor(session_name);
 329         if (!session_descriptor) {
 330                 ret = CMD_ERROR;
 331                 goto error;
 332         }
 333         ret_code = lttng_create_session_ext(session_descriptor);
 334         if (ret_code != LTTNG_OK) {
 335                 ERR("%s", lttng_strerror(-ret_code));
 336                 ret = CMD_ERROR;
 337                 goto error;
 338         }
 339
 340         descriptor_status = lttng_session_descriptor_get_session_name(session_descriptor,
 341                                                                       &created_session_name);
 342         if (descriptor_status != LTTNG_SESSION_DESCRIPTOR_STATUS_OK) {
 343                 ERR("Failed to obtain created session name");
 344                 ret = CMD_ERROR;
 345                 goto error;
 346         }
 347
 348         ret = lttng_list_sessions(&sessions);
 349         if (ret < 0) {
 350                 ERR("Failed to fetch properties of created session: %s", lttng_strerror(ret));
 351                 ret = CMD_ERROR;
 352                 goto error;
 353         }
 354         for (i = 0; i < ret; i++) {
 355                 if (!strcmp(created_session_name, sessions[i].name)) {
 356                         created_session = &sessions[i];
 357                         break;
 358                 }
 359         }
 360         if (!created_session) {
 361                 ERR("Failed to fetch properties of created session");
 362                 ret = CMD_ERROR;
 363                 goto error;
 364         }
 365
 366         if (opt_shm_path) {
 367                 char datetime_suffix[17] = {};
 368
 369                 /*
 370                  * An auto-generated session name already includes the creation
 371                  * timestamp.
 372                  */
 373                 if (session_name) {
 374                         uint64_t creation_time;
 375                         struct tm *timeinfo;
 376                         time_t creation_time_t;
 377                         size_t strftime_ret;
 378
 379                         ret_code = lttng_session_get_creation_time(created_session, &creation_time);
 380                         if (ret_code != LTTNG_OK) {
 381                                 ERR("%s", lttng_strerror(-ret_code));
 382                                 ret = CMD_ERROR;
 383                                 goto error;
 384                         }
 385                         creation_time_t = (time_t) creation_time;
 386                         timeinfo = localtime(&creation_time_t);
 387                         if (!timeinfo) {
 388                                 PERROR("Failed to interpret session creation time");
 389                                 ret = CMD_ERROR;
 390                                 goto error;
 391                         }
 392                         strftime_ret = strftime(datetime_suffix,
 393                                                 sizeof(datetime_suffix),
 394                                                 "-%Y%m%d-%H%M%S",
 395                                                 timeinfo);
 396                         if (strftime_ret == 0) {
 397                                 ERR("Failed to format session creation time.");
 398                                 ret = CMD_ERROR;
 399                                 goto error;
 400                         }
 401                 }
 402
 403                 ret = snprintf(shm_path,
 404                                sizeof(shm_path),
 405                                "%s/%s%s",
 406                                opt_shm_path,
 407                                created_session_name,
 408                                datetime_suffix);
 409                 if (ret < 0 || ret >= sizeof(shm_path)) {
 410                         ERR("Failed to format the shared memory path.");
 411                         ret = CMD_ERROR;
 412                         goto error;
 413                 }
 414                 ret = lttng_set_session_shm_path(created_session_name, shm_path);
 415                 if (ret < 0) {
 416                         lttng_destroy_session(created_session_name);
 417                         ret = CMD_ERROR;
 418                         goto error;
 419                 }
 420         }
 421
 422         if (opt_snapshot) {
 423                 MSG("Snapshot session %s created.", created_session_name);
 424         } else if (opt_live_timer) {
 425                 MSG("Live session %s created.", created_session_name);
 426         } else {
 427                 MSG("Session %s created.", created_session_name);
 428         }
 429
 430         if (*created_session->path && !opt_snapshot) {
 431                 MSG("Traces will be output to %s", created_session->path);
 432
 433                 if (opt_live_timer) {
 434                         MSG("Live timer interval set to %u %s", opt_live_timer, USEC_UNIT);
 435                 }
 436         } else if (opt_snapshot) {
 437                 struct lttng_snapshot_output_list *list;
 438                 struct lttng_snapshot_output *iter;
 439                 char snapshot_url[LTTNG_PATH_MAX] = {};
 440
 441                 ret = lttng_snapshot_list_output(created_session_name, &list);
 442                 if (ret < 0) {
 443                         ERR("Failed to list snapshot outputs.");
 444                         ret = CMD_ERROR;
 445                         goto error;
 446                 }
 447
 448                 while ((iter = lttng_snapshot_output_list_get_next(list))) {
 449                         const char *url = nullptr;
 450
 451                         url = lttng_snapshot_output_get_ctrl_url(iter);
 452                         ret = lttng_strncpy(snapshot_url, url, sizeof(snapshot_url));
 453                         if (ret) {
 454                                 snapshot_url[0] = '\0';
 455                                 ERR("Failed to retrieve snapshot output destination");
 456                         }
 457                         break;
 458                 }
 459                 lttng_snapshot_output_list_destroy(list);
 460
 461                 if (*snapshot_url) {
 462                         MSG("Default snapshot output set to %s", snapshot_url);
 463                 }
 464                 MSG("Every channel enabled for this session will be set to mmap output and default to overwrite mode.");
 465         }
 466         if (opt_shm_path) {
 467                 MSG("Shared memory path set to %s", shm_path);
 468         }
 469
 470         /* Mi output */
 471         if (lttng_opt_mi) {
 472                 ret = mi_created_session(created_session_name);
 473                 if (ret) {
 474                         ret = CMD_ERROR;
 475                         goto error;
 476                 }
 477         }
 478
 479         /* Init lttng session config */
 480         ret = config_init(created_session_name);
 481         if (ret < 0) {
 482                 MSG("Unable to initialize configuration for created session: future commands will require the target session name explicitly");
 483                 ret = CMD_WARNING;
 484                 goto error;
 485         }
 486
 487         ret = CMD_SUCCESS;
 488 error:
 489         lttng_session_descriptor_destroy(session_descriptor);
 490         free(sessions);
 491         return ret;
 492 }
 493
 494 /*
 495  *  spawn_sessiond
 496  *
 497  *  Spawn a session daemon by forking and execv.
 498  */
 499 static int spawn_sessiond(const char *pathname)
 500 {
 501         int ret = 0;
 502         pid_t pid;
 503
 504         MSG("Spawning a session daemon");
 505         pid = fork();
 506         if (pid == 0) {
 507                 /*
 508                  * Spawn session daemon in daemon mode.
 509                  */
 510                 execlp(pathname, "lttng-sessiond", "--daemonize", NULL);
 511                 /* execlp only returns if error happened */
 512                 if (errno == ENOENT) {
 513                         ERR("No session daemon found. Use --sessiond-path.");
 514                 } else {
 515                         PERROR("execlp");
 516                 }
 517                 kill(getppid(), SIGTERM); /* wake parent */
 518                 exit(EXIT_FAILURE);
 519         } else if (pid > 0) {
 520                 /*
 521                  * In daemon mode (--daemonize), sessiond only exits when
 522                  * it's ready to accept commands.
 523                  */
 524                 for (;;) {
 525                         int status;
 526                         pid_t wait_pid_ret = waitpid(pid, &status, 0);
 527
 528                         if (wait_pid_ret < 0) {
 529                                 if (errno == EINTR) {
 530                                         continue;
 531                                 }
 532                                 PERROR("waitpid");
 533                                 ret = -errno;
 534                                 goto end;
 535                         }
 536
 537                         if (WIFSIGNALED(status)) {
 538                                 ERR("Session daemon was killed by signal %d", WTERMSIG(status));
 539                                 ret = -1;
 540                                 goto end;
 541                         } else if (WIFEXITED(status)) {
 542                                 DBG("Session daemon terminated normally (exit status: %d)",
 543                                     WEXITSTATUS(status));
 544
 545                                 if (WEXITSTATUS(status) != 0) {
 546                                         ERR("Session daemon terminated with an error (exit status: %d)",
 547                                             WEXITSTATUS(status));
 548                                         ret = -1;
 549                                         goto end;
 550                                 }
 551                                 break;
 552                         }
 553                 }
 554
 555                 goto end;
 556         } else {
 557                 PERROR("fork");
 558                 ret = -1;
 559                 goto end;
 560         }
 561
 562 end:
 563         return ret;
 564 }
 565
 566 /*
 567  *  launch_sessiond
 568  *
 569  *  Check if the session daemon is available using
 570  *  the liblttngctl API for the check. If not, try to
 571  *  spawn a daemon.
 572  */
 573 static int launch_sessiond()
 574 {
 575         int ret;
 576         const char *pathname = nullptr;
 577
 578         ret = lttng_session_daemon_alive();
 579         if (ret) {
 580                 /* Sessiond is alive, not an error */
 581                 ret = 0;
 582                 goto end;
 583         }
 584
 585         /* Try command line option path */
 586         pathname = opt_sessiond_path;
 587
 588         /* Try LTTNG_SESSIOND_PATH env variable */
 589         if (pathname == nullptr) {
 590                 pathname = getenv(DEFAULT_SESSIOND_PATH_ENV);
 591         }
 592
 593         /* Try with configured path */
 594         if (pathname == nullptr) {
 595                 if (CONFIG_SESSIOND_BIN[0] != '\0') {
 596                         pathname = CONFIG_SESSIOND_BIN;
 597                 }
 598         }
 599
 600         /* Try the default path */
 601         if (pathname == nullptr) {
 602                 pathname = INSTALL_BIN_PATH "/lttng-sessiond";
 603         }
 604
 605         DBG("Session daemon binary path: %s", pathname);
 606
 607         /* Check existence and permissions */
 608         ret = access(pathname, F_OK | X_OK);
 609         if (ret < 0) {
 610                 ERR("No such file or access denied: %s", pathname);
 611                 goto end;
 612         }
 613
 614         ret = spawn_sessiond(pathname);
 615 end:
 616         if (ret) {
 617                 ERR("Problem occurred while launching session daemon (%s)", pathname);
 618         }
 619         return ret;
 620 }
 621
 622 static int validate_url_option_combination()
 623 {
 624         int ret = 0;
 625         int used_count = 0;
 626
 627         used_count += !!opt_url;
 628         used_count += !!opt_output_path;
 629         used_count += (opt_data_url || opt_ctrl_url);
 630         if (used_count > 1) {
 631                 ERR("Only one of the --set-url, --ctrl-url/data-url, or --output options may be used at once.");
 632                 ret = -1;
 633         }
 634
 635         return ret;
 636 }
 637
 638 /*
 639  *  The 'create <options>' first level command
 640  *
 641  *  Returns one of the CMD_* result constants.
 642  */
 643 int cmd_create(int argc, const char **argv)
 644 {
 645         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 646         char *opt_arg = nullptr;
 647         const char *arg_session_name = nullptr;
 648         const char *leftover = nullptr;
 649         static poptContext pc;
 650
 651         pc = poptGetContext(nullptr, argc, argv, long_options, 0);
 652         poptReadDefaultConfig(pc, 0);
 653
 654         while ((opt = poptGetNextOpt(pc)) != -1) {
 655                 switch (opt) {
 656                 case OPT_HELP:
 657                         SHOW_HELP();
 658                         goto end;
 659                 case OPT_LIST_OPTIONS:
 660                         list_cmd_options(stdout, long_options);
 661                         goto end;
 662                 case OPT_LIVE_TIMER:
 663                 {
 664                         uint64_t v;
 665
 666                         errno = 0;
 667                         if (opt_arg) {
 668                                 free(opt_arg);
 669                                 opt_arg = nullptr;
 670                         }
 671
 672                         opt_arg = poptGetOptArg(pc);
 673                         if (!opt_arg) {
 674                                 /* Set up default values. */
 675                                 opt_live_timer = (uint32_t) DEFAULT_LTTNG_LIVE_TIMER;
 676                                 DBG("Session live timer interval set to default value %d",
 677                                     opt_live_timer);
 678                                 break;
 679                         }
 680
 681                         if (utils_parse_time_suffix(opt_arg, &v) < 0) {
 682                                 ERR("Wrong value for --live parameter: %s", opt_arg);
 683                                 ret = CMD_ERROR;
 684                                 goto end;
 685                         }
 686
 687                         if (v != (uint32_t) v) {
 688                                 ERR("32-bit overflow in --live parameter: %s", opt_arg);
 689                                 ret = CMD_ERROR;
 690                                 goto end;
 691                         }
 692
 693                         if (v == 0) {
 694                                 ERR("Live timer interval must be greater than zero");
 695                                 ret = CMD_ERROR;
 696                                 goto end;
 697                         }
 698
 699                         opt_live_timer = (uint32_t) v;
 700                         DBG("Session live timer interval set to %d", opt_live_timer);
 701                         break;
 702                 }
 703                 default:
 704                         ret = CMD_UNDEFINED;
 705                         goto end;
 706                 }
 707         }
 708
 709         if (opt_no_consumer) {
 710                 MSG("The option --no-consumer is obsolete. Use --no-output now.");
 711                 ret = CMD_WARNING;
 712                 goto end;
 713         }
 714
 715         ret = validate_url_option_combination();
 716         if (ret) {
 717                 ret = CMD_ERROR;
 718                 goto end;
 719         }
 720
 721         /* Spawn a session daemon if needed */
 722         if (!opt_no_sessiond) {
 723                 ret = launch_sessiond();
 724                 if (ret) {
 725                         ret = CMD_ERROR;
 726                         goto end;
 727                 }
 728         }
 729
 730         /* MI initialization */
 731         if (lttng_opt_mi) {
 732                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 733                 if (!writer) {
 734                         ret = -LTTNG_ERR_NOMEM;
 735                         goto end;
 736                 }
 737
 738                 /* Open command element */
 739                 ret = mi_lttng_writer_command_open(writer, mi_lttng_element_command_create);
 740                 if (ret) {
 741                         ret = CMD_ERROR;
 742                         goto end;
 743                 }
 744
 745                 /* Open output element */
 746                 ret = mi_lttng_writer_open_element(writer, mi_lttng_element_command_output);
 747                 if (ret) {
 748                         ret = CMD_ERROR;
 749                         goto end;
 750                 }
 751         }
 752
 753         /* Get the optional session name argument. */
 754         arg_session_name = poptGetArg(pc);
 755
 756         leftover = poptGetArg(pc);
 757         if (leftover) {
 758                 ERR("Unknown argument: %s", leftover);
 759                 ret = CMD_ERROR;
 760                 goto end;
 761         }
 762
 763         command_ret = create_session(arg_session_name);
 764         if (command_ret) {
 765                 success = 0;
 766         }
 767
 768         if (lttng_opt_mi) {
 769                 /* Close  output element */
 770                 ret = mi_lttng_writer_close_element(writer);
 771                 if (ret) {
 772                         ret = CMD_ERROR;
 773                         goto end;
 774                 }
 775
 776                 /* Success ? */
 777                 ret = mi_lttng_writer_write_element_bool(
 778                         writer, mi_lttng_element_command_success, success);
 779                 if (ret) {
 780                         ret = CMD_ERROR;
 781                         goto end;
 782                 }
 783
 784                 /* Command element close */
 785                 ret = mi_lttng_writer_command_close(writer);
 786                 if (ret) {
 787                         ret = CMD_ERROR;
 788                         goto end;
 789                 }
 790         }
 791
 792 end:
 793         /* Mi clean-up */
 794         if (writer && mi_lttng_writer_destroy(writer)) {
 795                 /* Preserve original error code */
 796                 ret = ret ? ret : -LTTNG_ERR_MI_IO_FAIL;
 797         }
 798
 799         /* Overwrite ret if an error occurred in create_session() */
 800         ret = command_ret ? command_ret : ret;
 801
 802         free(opt_arg);
 803         poptFreeContext(pc);
 804         return ret;
 805 }